Common Operations of DataTable in C,

Common Operations of DataTable in C,

1. Convert the generic collection class to a able (used when there is no data in the table ):

  public static DataTable NullListToDataTable(IList list)        {            var result = new DataTable();            if (list.Count <= 0) return result;            var propertys = list[0].GetType().GetProperties();            foreach (var pi in propertys)            {                if (pi != null)                {                    result.Columns.Add(pi.Name, pi.PropertyType);                }            }            for (var i = 0; i < list.Count; i++)            {                var tempList = new ArrayList();                foreach (var pi in propertys)                {                    var obj = pi.GetValue(list[i], null);                    tempList.Add(obj);                }                var array = tempList.ToArray();                result.LoadDataRow(array, true);            }            return result;        }

2. Convert the generic collection class to a able (used when the table contains data ):

 public static DataTable NoNullListToDataTable<T>(IList<T> list)        {            var ds = new DataSet();            var dt = new DataTable(typeof(T).Name);            var myPropertyInfo =                typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);            foreach (var t in list)            {                if (t == null) continue;                var row = dt.NewRow();                for (int i = 0, j = myPropertyInfo.Length; i < j; i++)                {                    var pi = myPropertyInfo[i];                    var name = pi.Name;                    if (dt.Columns[name] != null) continue;                    DataColumn column;                    if (pi.PropertyType.UnderlyingSystemType.ToString() == "System.Nullable`1[System.Int32]")                    {                        column = new DataColumn(name, typeof(int));                        dt.Columns.Add(column);                        if (pi.GetValue(t, null) != null)                            row[name] = pi.GetValue(t, null);                        else                            row[name] = DBNull.Value;                    }                    else                    {                        column = new DataColumn(name, pi.PropertyType);                        dt.Columns.Add(column);                        row[name] = pi.GetValue(t, null);                    }                }                dt.Rows.Add(row);            }            ds.Tables.Add(dt);            return ds.Tables[0];        }

3. If the table contains data or no data, you can exclude that DATASET does not support System. Nullable errors:

 public static DataTable ToDataTable<T>(IList<T> list)        {            if (list == null || list.Count <= 0)            {                var result = new DataTable();                object temp;                if (list == null || list.Count <= 0) return result;                var propertys = list[0].GetType().GetProperties();                foreach (var pi in propertys)                {                    {                        result.Columns.Add(pi.Name, pi.PropertyType);                    }                }                for (var i = 0; i < list.Count; i++)                {                    var tempList = new ArrayList();                    foreach (var pi in propertys)                    {                        var obj = pi.GetValue(list[i], null);                        tempList.Add(obj);                    }                    var array = tempList.ToArray();                    result.LoadDataRow(array, true);                }                return result;            }            var ds = new DataSet();            var dt = new DataTable(typeof(T).Name);            var myPropertyInfo =                typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);            foreach (var t in list)            {                if (t == null) continue;                var row = dt.NewRow();                for (int i = 0, j = myPropertyInfo.Length; i < j; i++)                {                    var pi = myPropertyInfo[i];                    var name = pi.Name;                    if (dt.Columns[name] != null) continue;                    DataColumn column;                    if (pi.PropertyType.UnderlyingSystemType.ToString() == "System.Nullable`1[System.Int32]")                    {                        column = new DataColumn(name, typeof(int));                        dt.Columns.Add(column);                        if (pi.GetValue(t, null) != null)                            row[name] = pi.GetValue(t, null);                        else                            row[name] = DBNull.Value;                    }                    else                    {                        column = new DataColumn(name, pi.PropertyType);                        dt.Columns.Add(column);                        row[name] = pi.GetValue(t, null);                    }                }                dt.Rows.Add(row);            }            ds.Tables.Add(dt);            return ds.Tables[0];        }

4. Merge the same able:

   public static DataTable MergeSameDatatable(DataTable dataTable1, DataTable dataTable2)        {            var newDataTable = dataTable1.Clone();            var obj = new object[newDataTable.Columns.Count];            for (var i = 0; i < dataTable1.Rows.Count; i++)            {                dataTable1.Rows[i].ItemArray.CopyTo(obj, 0);                newDataTable.Rows.Add(obj);            }            for (var i = 0; i < dataTable2.Rows.Count; i++)            {                dataTable2.Rows[i].ItemArray.CopyTo(obj, 0);                newDataTable.Rows.Add(obj);            }            return new DataTable();        }

5. merge two different able columns into a new DataTable:

 public static DataTable UniteDataTable(DataTable dt1, DataTable dt2, string dtName)        {            var dt3 = dt1.Clone();            for (var i = 0; i < dt2.Columns.Count; i++)            {                dt3.Columns.Add(dt2.Columns[i].ColumnName);            }            var obj = new object[dt3.Columns.Count];            for (int i = 0; i < dt1.Rows.Count; i++)            {                dt1.Rows[i].ItemArray.CopyTo(obj, 0);                dt3.Rows.Add(obj);            }            if (dt1.Rows.Count >= dt2.Rows.Count)            {                for (var i = 0; i < dt2.Rows.Count; i++)                {                    for (var j = 0; j < dt2.Columns.Count; j++)                    {                        dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                    }                }            }            else            {                for (var i = 0; i < dt2.Rows.Count - dt1.Rows.Count; i++)                {                    var dr3 = dt3.NewRow();                    dt3.Rows.Add(dr3);                }                for (var i = 0; i < dt2.Rows.Count; i++)                {                    for (var j = 0; j < dt2.Columns.Count; j++)                    {                        dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                    }                }            }            dt3.TableName = dtName;            return dt3;        }

6. Datatable to List <Dictionary <string, object>:

 public static List<Dictionary<string, object>> DataTableToListDictory(DataTable table)        {            var ld = new List<Dictionary<string, object>>();            for (var i = 0; i < table.Rows.Count; i++)            {                var dic = new Dictionary<string, object>();                for (var j = 0; j < table.Columns.Count; j++)                {                    dic.Add(table.Columns[j].ColumnName, table.Rows[i][j]);                }                ld.Add(dic);            }            return ld;        }